Transportation Research Part B: Methodological, 2017
through simulation and numerical results that the new policy outperforms the original BackPressur... more through simulation and numerical results that the new policy outperforms the original BackPressure-based distributed control scheme both in terms of network throughput and other congestion measures such as travel time.
MAC layer constraints � Broadcast performance enhancement � Disseminate safety messages � to all ... more MAC layer constraints � Broadcast performance enhancement � Disseminate safety messages � to all nearby vehicles � within time constraint � Latency should be kept minimum (100ms ~ 400ms) � Packet Delivery Ratio (PDR)> 90%
Quality of Service and Resource Allocation in WiMAX, 2012
(UGS) is designed for real-time applications with constant data rate. These applications always h... more (UGS) is designed for real-time applications with constant data rate. These applications always have stringent delay requirement, such as T1/E1. 2. Real-time polling service (rtPS) is designed for real-time applications with variable data rate. These applications have less stringent delay requirement, such as MPEG and VoIP without silence suppression. 3. Extended real-time polling service (ertPS) builds on the efficiency of both UGS and rtPS. It is designed for the applications with variable data rate such as VoIP with silence suppression. 4. Non-real-time polling service (nrtPS) is designed to support variable bit rate non-real-time applications with certain bandwidth guarantee, such as high bandwidth FTP. 5. Best effort service (BE) is designed for best effort applications such as HTTP. To meet the requirements of different service classes, several bandwidth request mechanisms have been defined, namely, unsolicited granting, unicast polling, broadcast polling and piggybacking. In this chapter, we present a performance model for services, such as BE service, based on the broadcast polling mechanism which is contention based and requires 8 www.intechopen.com
2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577), 2004
Limited wavelength conversion and deflection routing are considered as viable methods to reduce t... more Limited wavelength conversion and deflection routing are considered as viable methods to reduce the burst blocking probability in optical burst switched (OBS) networks. The question of which of the two methods is most effective has yet to be resolved. In this paper, an analytical model is derived that provides an accurate and quick means to evaluate and compare the effectiveness of limited wavelength conversion and deflection routing. First, an overflow load fixed point approximation model is derived for a single link in isolation. Then the single link model is integrated into a reduced load fixed point approximation model for a general network topology with deflection routing. The accuracy of the analytical model is verified through simulation.
Transportation Research Part C: Emerging Technologies, 2015
We propose in this paper a decentralized traffic signal control policy for urban road networks. O... more We propose in this paper a decentralized traffic signal control policy for urban road networks. Our policy is an adaptation of a so-called BackPressure scheme which has been widely recognized in data network as an optimal throughput control policy. We have formally proved that our proposed BackPressure scheme, with fixed cycle time and cyclic phases, stabilizes the network for any feasible traffic demands. Simulation has been conducted to compare our BackPressure policy against other existing distributed control policies in various traffic and network scenarios. Numerical results suggest that the proposed policy can surpass other policies both in terms of network throughput and congestion.
Wireless Communications and Networking, IEEE Conference, 2006
This paper proposes a new call quality measure based on mobile signal strength measurements to ev... more This paper proposes a new call quality measure based on mobile signal strength measurements to evaluate performance of handoff algorithms in wireless cellular networks. The proposed measure allows the quantification of the impact of the handoff algorithms of performance. Using the proposed measure we compare existing handoff algorithms to identify the trade-off between signal quality and required number of handoffs.
2008 New Technologies, Mobility and Security, 2008
We propose in this paper an analytical model to evaluate the average packet delay and its standar... more We propose in this paper an analytical model to evaluate the average packet delay and its standard deviation in a saturated IEEE 802.16 network with the binary exponential backoff mechanism. In particular, we develop a simple fixed point analysis to approximate the probability that a bandwidth request is unsuccessful in such a network. A closed form expression for the mean and standard deviation of the delay are then derived from the model as a function of the system parameters. The accuracy of the analytical model is evaluated by comparing with simulation results over a wide range of operating conditions.
2009 IEEE 34th Conference on Local Computer Networks, 2009
Wireless voice over IP (VoIP) is an important emerging service in telecommunications due to its p... more Wireless voice over IP (VoIP) is an important emerging service in telecommunications due to its potential for replacing cell phone communication wherever wireless local area network (WLAN) is installed. Recent studies, however, suggest that the number of voice calls that can be supported in the widely deployed IEEE 802.11 WLAN is limited. In this paper, we utilize a so-called transmission opportunity (TXOP) parameter of a medium access control protocol as a simple solution to improve the VoIP capacity. We provide a detailed analytical model to show that the capacity can be improved significantly, and discuss the implications of the TXOP parameter in terms of the maximum number of calls the 802.11 network can support. The analytical results are validated by simulations for a wide range of parameters. Furthermore we investigate the impact of the buffer at the access point (AP) on the number of obtainable voice calls. We show that there exists an optimal buffer size where the maximum voice capacity is achieved, but further increasing the buffer beyond this value will not result in an increased voice capacity. Based on this finding a closed form expression for the maximum number of voice calls is developed as a function of TXOP value. Finally, we propose a simple yet accurate voice capacity approximation formula for voice capacity estimation in WLAN and provide some insights that an be gained from this formula.
2010 IEEE Wireless Communication and Networking Conference, 2010
Seamless handoff between different wireless technologies is a vital requirement for the next gene... more Seamless handoff between different wireless technologies is a vital requirement for the next generation mobile networks (NGMN). The soft handoff (SHO) method provides seamless roaming, but makes heavy use of battery and radio resources. In this paper, we propose a conservative soft handoff (cSHO) which maintains the benefits of SHO and reduces the consumption of resources. Instead of using both radio interfaces during the handoff period, the mobile station (MS) activates and deactivates its radio interfaces and switches between them to maintain the best possible radio connection. Since multimedia packets are already duplicated in the network and buffered in the base stations, fast switching between interfaces is possible. We investigate the performance of our proposed scheme by simulation and compare the performance of the cSHO scheme with the SHO and hard handoff (HHO) mechanisms. This full text paper was peer reviewed at the direction of IEEE Communications Society subject matter experts for publication in the WCNC 2010 proceedings.
IEEE International Conference on Communications, 2003. ICC '03.
This paper provides an efficient solution for the derivation of the delay distribution for a TDMA... more This paper provides an efficient solution for the derivation of the delay distribution for a TDMA system with a finite buffer. Assuming successive intervals of length equal to the duration of a slot, the density is expressed as (finite) linear combinations of gamma densities and beta densities with positive coefficients. The results are verified by simulations. Comparison with a previously proposed solution demonstrates that the solution presented here is more efficient.
2007 9th International Conference on Transparent Optical Networks, 2007
A key technique for reducing packet blocking in optical switches is by temporarily buffering pack... more A key technique for reducing packet blocking in optical switches is by temporarily buffering packets in fiber delay lines (FDLs). The packet blocking probability depend on the FDLs design as well as on how packets are scheduled to the FDL buffers. This study compares between the blocking probabilities of the following design and buffer scheduler options: (i) input vs output port FDLs; (ii) shared vs port-dependent FDLs; (iii) forward vs feedback FDLs; (iv) variable vs fixed size FDLs; and (v) FIFO vs non-overlapping buffer schedulers. The comparison results reveals several interesting facts. The first one is that feedback FDL design can reduce the number of required buffers by 7500 compared with a forward FDL design. Another observed fact is that fixed-size FDLs is very wasteful, specifically, the length of a fixed size FDL has no affect on the blocking probability. The third observation is that a non-overlapping buffer scheduler can reduce the number of required FDLs by 3000 compared with a FIFO scheduler.
2008 New Technologies, Mobility and Security, 2008
In this paper, we propose an analytical model to evaluate the average packet delay and its standa... more In this paper, we propose an analytical model to evaluate the average packet delay and its standard deviation in a saturated IEEE 802.16 network. In addition, the bandwidth utilization of an uplink data frame and packet loss probability are also derived from the model. We show that our analytical model is accurate for a range of parameters by comparing it with simulation results. Using the analytical model we then suggest an appropriate parameter setting for the uplink data frame to better utilize the bandwidth and to minimize the packet loss probability for both saturated and unsaturated networks.
Wireless voice over internet protocol (VoIP) is an important emerging service in telecommunicatio... more Wireless voice over internet protocol (VoIP) is an important emerging service in telecommunication due to its potential for replacing cell phone communication wherever a wireless local area network (WLAN) is installed. Recent studies, however, suggest that the number of voice calls that can be supported in the widely deployed IEEE 802.11 WLAN is limited. In this paper, we utilize a so-called transmission opportunity (TXOP) parameter of a medium access control (MAC) protocol as a simple solution to improve the VoIP capacity. We provide a detailed analytical model to show that the capacity can significantly be improved and discuss the implications of the TXOP parameter in terms of the maximum number of calls the IEEE 802.11 network can support. The analytical results are validated by simulations for a wide range of parameters. Furthermore, we investigate the impact of the buffer at the access point (AP) on the number of obtainable voice calls. We show that there exists an optimal buffer size where the maximum voice capacity is achieved, but further increasing the buffer beyond this value will not result in an increased voice capacity. Based on this finding, a closed-form expression for the maximum number of voice calls is developed as a function of the TXOP value. Finally, we propose a simple yet accurate approximation for voice-capacity estimation and provide some insights gained from the approximation. Index Terms-Buffer size, enhanced distributed channel access (EDCA), IEEE 802.11 wireless LAN, transmission opportunity (TXOP), voice-over-internet protocol (VoIP) capacity. I. INTRODUCTION I N recent years, IEEE 802.11 wireless local area networks (WLANs) have become more readily available to the public. Many places such as cafes, restaurants, and airport lounges now offer free wireless access. Decreasing costs for wireless equipment and, subsequently, the integration of IEEE 802.11 technologies in mobile devices such as laptops, pocket PCs, and cell phones have driven an increased demand for wireless access. As wireless becomes more accessible, wireless voice over internet protocol (VoIP) is an important emerging service due to its low cost and its potential for replacing cell phone communication wherever a WLAN is installed. However, recent studies [1]-[5] suggest that the number of voice calls that can be supported in a WLAN is limited. For example, only five
The IEEE 802.16 standard is a promising technology for the fourth-generation mobile networks and ... more The IEEE 802.16 standard is a promising technology for the fourth-generation mobile networks and is being actively promoted by the WiMAX Forum, an industry-led consortium. Among the various service classes supported in the standard, best-effort service is expected to be the major service class subscribed to by users due to its operational simplicity and lower charging rate compared with other service classes. In this paper, we investigate the throughput and packet access delay performance of the best-effort service using the contentionbased bandwidth request mechanism in a saturated 802.16 network. In particular, we develop a simple fixed point analysis to approximate the failure probability of a bandwidth request and derive analytical expressions for network throughput and packet access delay. Furthermore, the uniqueness of the fixed point is established. The accuracy of the analytical model is validated by comparing with simulation over a wide range of operating conditions. The implications of various different parameter configurations on the system performance are investigated using the analytical model. The utility of the model is further demonstrated by finding the maximum achievable throughput and obtaining its corresponding optimal initial contention window.
We propose a new framework, based on signal quality, for performance evaluation and comparison be... more We propose a new framework, based on signal quality, for performance evaluation and comparison between existing handoff algorithms. It includes new call quality measures and an off-line cluster-based computationally-simple heuristic algorithm to find a near optimal handoff sequence used as a benchmark. We then compare existing handoff algorithms and identify the trade-off between signal quality and number of handoffs.
We provide teletraffic models for loss probability evaluation of optical burst switching (OBS). W... more We provide teletraffic models for loss probability evaluation of optical burst switching (OBS). We show that the popular Engset formula is not exact for OBS modeling and demonstrate that in certain cases it is not appropriate. A new exact model is provided. The various models are compared using numerical results for various OBS alternatives with and without Burst Segmentation.
Transmission of the acknowledgement frame after a packet reception is optional in the IEEE 802.15... more Transmission of the acknowledgement frame after a packet reception is optional in the IEEE 802.15.4 standard. Considering a set of sensor nodes, each of which has a packet to transmit at the beginning of an active period, we provide an analysis that yields the packet loss statistics of the nonacknowledgement mode of the standard. The analysis is based on a non-stationary Markov chain model and its accuracy is verified by ns-2 simulations.
In this letter, we derive the asymptotic behavior of the ratio between the blocking probabilities... more In this letter, we derive the asymptotic behavior of the ratio between the blocking probabilities of burst segmentation (BS) and just-enough-time (JET) policies in an optical burst switch. It is shown that if the ratio between the offered load and the number of wavelengths, , is fixed and equals as the number of wavelengths approaches infinity, the ratio between the blocking probabilities of BS and JET approaches 1 if 1; 0.5 if = 1; and is (1) with a constant (1) 2 if 1.
This letter proposes a method to strictly prioritize switching access in Just-Enough-Time (JET)-b... more This letter proposes a method to strictly prioritize switching access in Just-Enough-Time (JET)-based optical burst switching networks. A queueing model is developed by which the blocking probability for each traffic class can be analytically evaluated. The analytical results are validated by simulations.
Transportation Research Part B: Methodological, 2017
through simulation and numerical results that the new policy outperforms the original BackPressur... more through simulation and numerical results that the new policy outperforms the original BackPressure-based distributed control scheme both in terms of network throughput and other congestion measures such as travel time.
MAC layer constraints � Broadcast performance enhancement � Disseminate safety messages � to all ... more MAC layer constraints � Broadcast performance enhancement � Disseminate safety messages � to all nearby vehicles � within time constraint � Latency should be kept minimum (100ms ~ 400ms) � Packet Delivery Ratio (PDR)> 90%
Quality of Service and Resource Allocation in WiMAX, 2012
(UGS) is designed for real-time applications with constant data rate. These applications always h... more (UGS) is designed for real-time applications with constant data rate. These applications always have stringent delay requirement, such as T1/E1. 2. Real-time polling service (rtPS) is designed for real-time applications with variable data rate. These applications have less stringent delay requirement, such as MPEG and VoIP without silence suppression. 3. Extended real-time polling service (ertPS) builds on the efficiency of both UGS and rtPS. It is designed for the applications with variable data rate such as VoIP with silence suppression. 4. Non-real-time polling service (nrtPS) is designed to support variable bit rate non-real-time applications with certain bandwidth guarantee, such as high bandwidth FTP. 5. Best effort service (BE) is designed for best effort applications such as HTTP. To meet the requirements of different service classes, several bandwidth request mechanisms have been defined, namely, unsolicited granting, unicast polling, broadcast polling and piggybacking. In this chapter, we present a performance model for services, such as BE service, based on the broadcast polling mechanism which is contention based and requires 8 www.intechopen.com
2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577), 2004
Limited wavelength conversion and deflection routing are considered as viable methods to reduce t... more Limited wavelength conversion and deflection routing are considered as viable methods to reduce the burst blocking probability in optical burst switched (OBS) networks. The question of which of the two methods is most effective has yet to be resolved. In this paper, an analytical model is derived that provides an accurate and quick means to evaluate and compare the effectiveness of limited wavelength conversion and deflection routing. First, an overflow load fixed point approximation model is derived for a single link in isolation. Then the single link model is integrated into a reduced load fixed point approximation model for a general network topology with deflection routing. The accuracy of the analytical model is verified through simulation.
Transportation Research Part C: Emerging Technologies, 2015
We propose in this paper a decentralized traffic signal control policy for urban road networks. O... more We propose in this paper a decentralized traffic signal control policy for urban road networks. Our policy is an adaptation of a so-called BackPressure scheme which has been widely recognized in data network as an optimal throughput control policy. We have formally proved that our proposed BackPressure scheme, with fixed cycle time and cyclic phases, stabilizes the network for any feasible traffic demands. Simulation has been conducted to compare our BackPressure policy against other existing distributed control policies in various traffic and network scenarios. Numerical results suggest that the proposed policy can surpass other policies both in terms of network throughput and congestion.
Wireless Communications and Networking, IEEE Conference, 2006
This paper proposes a new call quality measure based on mobile signal strength measurements to ev... more This paper proposes a new call quality measure based on mobile signal strength measurements to evaluate performance of handoff algorithms in wireless cellular networks. The proposed measure allows the quantification of the impact of the handoff algorithms of performance. Using the proposed measure we compare existing handoff algorithms to identify the trade-off between signal quality and required number of handoffs.
2008 New Technologies, Mobility and Security, 2008
We propose in this paper an analytical model to evaluate the average packet delay and its standar... more We propose in this paper an analytical model to evaluate the average packet delay and its standard deviation in a saturated IEEE 802.16 network with the binary exponential backoff mechanism. In particular, we develop a simple fixed point analysis to approximate the probability that a bandwidth request is unsuccessful in such a network. A closed form expression for the mean and standard deviation of the delay are then derived from the model as a function of the system parameters. The accuracy of the analytical model is evaluated by comparing with simulation results over a wide range of operating conditions.
2009 IEEE 34th Conference on Local Computer Networks, 2009
Wireless voice over IP (VoIP) is an important emerging service in telecommunications due to its p... more Wireless voice over IP (VoIP) is an important emerging service in telecommunications due to its potential for replacing cell phone communication wherever wireless local area network (WLAN) is installed. Recent studies, however, suggest that the number of voice calls that can be supported in the widely deployed IEEE 802.11 WLAN is limited. In this paper, we utilize a so-called transmission opportunity (TXOP) parameter of a medium access control protocol as a simple solution to improve the VoIP capacity. We provide a detailed analytical model to show that the capacity can be improved significantly, and discuss the implications of the TXOP parameter in terms of the maximum number of calls the 802.11 network can support. The analytical results are validated by simulations for a wide range of parameters. Furthermore we investigate the impact of the buffer at the access point (AP) on the number of obtainable voice calls. We show that there exists an optimal buffer size where the maximum voice capacity is achieved, but further increasing the buffer beyond this value will not result in an increased voice capacity. Based on this finding a closed form expression for the maximum number of voice calls is developed as a function of TXOP value. Finally, we propose a simple yet accurate voice capacity approximation formula for voice capacity estimation in WLAN and provide some insights that an be gained from this formula.
2010 IEEE Wireless Communication and Networking Conference, 2010
Seamless handoff between different wireless technologies is a vital requirement for the next gene... more Seamless handoff between different wireless technologies is a vital requirement for the next generation mobile networks (NGMN). The soft handoff (SHO) method provides seamless roaming, but makes heavy use of battery and radio resources. In this paper, we propose a conservative soft handoff (cSHO) which maintains the benefits of SHO and reduces the consumption of resources. Instead of using both radio interfaces during the handoff period, the mobile station (MS) activates and deactivates its radio interfaces and switches between them to maintain the best possible radio connection. Since multimedia packets are already duplicated in the network and buffered in the base stations, fast switching between interfaces is possible. We investigate the performance of our proposed scheme by simulation and compare the performance of the cSHO scheme with the SHO and hard handoff (HHO) mechanisms. This full text paper was peer reviewed at the direction of IEEE Communications Society subject matter experts for publication in the WCNC 2010 proceedings.
IEEE International Conference on Communications, 2003. ICC '03.
This paper provides an efficient solution for the derivation of the delay distribution for a TDMA... more This paper provides an efficient solution for the derivation of the delay distribution for a TDMA system with a finite buffer. Assuming successive intervals of length equal to the duration of a slot, the density is expressed as (finite) linear combinations of gamma densities and beta densities with positive coefficients. The results are verified by simulations. Comparison with a previously proposed solution demonstrates that the solution presented here is more efficient.
2007 9th International Conference on Transparent Optical Networks, 2007
A key technique for reducing packet blocking in optical switches is by temporarily buffering pack... more A key technique for reducing packet blocking in optical switches is by temporarily buffering packets in fiber delay lines (FDLs). The packet blocking probability depend on the FDLs design as well as on how packets are scheduled to the FDL buffers. This study compares between the blocking probabilities of the following design and buffer scheduler options: (i) input vs output port FDLs; (ii) shared vs port-dependent FDLs; (iii) forward vs feedback FDLs; (iv) variable vs fixed size FDLs; and (v) FIFO vs non-overlapping buffer schedulers. The comparison results reveals several interesting facts. The first one is that feedback FDL design can reduce the number of required buffers by 7500 compared with a forward FDL design. Another observed fact is that fixed-size FDLs is very wasteful, specifically, the length of a fixed size FDL has no affect on the blocking probability. The third observation is that a non-overlapping buffer scheduler can reduce the number of required FDLs by 3000 compared with a FIFO scheduler.
2008 New Technologies, Mobility and Security, 2008
In this paper, we propose an analytical model to evaluate the average packet delay and its standa... more In this paper, we propose an analytical model to evaluate the average packet delay and its standard deviation in a saturated IEEE 802.16 network. In addition, the bandwidth utilization of an uplink data frame and packet loss probability are also derived from the model. We show that our analytical model is accurate for a range of parameters by comparing it with simulation results. Using the analytical model we then suggest an appropriate parameter setting for the uplink data frame to better utilize the bandwidth and to minimize the packet loss probability for both saturated and unsaturated networks.
Wireless voice over internet protocol (VoIP) is an important emerging service in telecommunicatio... more Wireless voice over internet protocol (VoIP) is an important emerging service in telecommunication due to its potential for replacing cell phone communication wherever a wireless local area network (WLAN) is installed. Recent studies, however, suggest that the number of voice calls that can be supported in the widely deployed IEEE 802.11 WLAN is limited. In this paper, we utilize a so-called transmission opportunity (TXOP) parameter of a medium access control (MAC) protocol as a simple solution to improve the VoIP capacity. We provide a detailed analytical model to show that the capacity can significantly be improved and discuss the implications of the TXOP parameter in terms of the maximum number of calls the IEEE 802.11 network can support. The analytical results are validated by simulations for a wide range of parameters. Furthermore, we investigate the impact of the buffer at the access point (AP) on the number of obtainable voice calls. We show that there exists an optimal buffer size where the maximum voice capacity is achieved, but further increasing the buffer beyond this value will not result in an increased voice capacity. Based on this finding, a closed-form expression for the maximum number of voice calls is developed as a function of the TXOP value. Finally, we propose a simple yet accurate approximation for voice-capacity estimation and provide some insights gained from the approximation. Index Terms-Buffer size, enhanced distributed channel access (EDCA), IEEE 802.11 wireless LAN, transmission opportunity (TXOP), voice-over-internet protocol (VoIP) capacity. I. INTRODUCTION I N recent years, IEEE 802.11 wireless local area networks (WLANs) have become more readily available to the public. Many places such as cafes, restaurants, and airport lounges now offer free wireless access. Decreasing costs for wireless equipment and, subsequently, the integration of IEEE 802.11 technologies in mobile devices such as laptops, pocket PCs, and cell phones have driven an increased demand for wireless access. As wireless becomes more accessible, wireless voice over internet protocol (VoIP) is an important emerging service due to its low cost and its potential for replacing cell phone communication wherever a WLAN is installed. However, recent studies [1]-[5] suggest that the number of voice calls that can be supported in a WLAN is limited. For example, only five
The IEEE 802.16 standard is a promising technology for the fourth-generation mobile networks and ... more The IEEE 802.16 standard is a promising technology for the fourth-generation mobile networks and is being actively promoted by the WiMAX Forum, an industry-led consortium. Among the various service classes supported in the standard, best-effort service is expected to be the major service class subscribed to by users due to its operational simplicity and lower charging rate compared with other service classes. In this paper, we investigate the throughput and packet access delay performance of the best-effort service using the contentionbased bandwidth request mechanism in a saturated 802.16 network. In particular, we develop a simple fixed point analysis to approximate the failure probability of a bandwidth request and derive analytical expressions for network throughput and packet access delay. Furthermore, the uniqueness of the fixed point is established. The accuracy of the analytical model is validated by comparing with simulation over a wide range of operating conditions. The implications of various different parameter configurations on the system performance are investigated using the analytical model. The utility of the model is further demonstrated by finding the maximum achievable throughput and obtaining its corresponding optimal initial contention window.
We propose a new framework, based on signal quality, for performance evaluation and comparison be... more We propose a new framework, based on signal quality, for performance evaluation and comparison between existing handoff algorithms. It includes new call quality measures and an off-line cluster-based computationally-simple heuristic algorithm to find a near optimal handoff sequence used as a benchmark. We then compare existing handoff algorithms and identify the trade-off between signal quality and number of handoffs.
We provide teletraffic models for loss probability evaluation of optical burst switching (OBS). W... more We provide teletraffic models for loss probability evaluation of optical burst switching (OBS). We show that the popular Engset formula is not exact for OBS modeling and demonstrate that in certain cases it is not appropriate. A new exact model is provided. The various models are compared using numerical results for various OBS alternatives with and without Burst Segmentation.
Transmission of the acknowledgement frame after a packet reception is optional in the IEEE 802.15... more Transmission of the acknowledgement frame after a packet reception is optional in the IEEE 802.15.4 standard. Considering a set of sensor nodes, each of which has a packet to transmit at the beginning of an active period, we provide an analysis that yields the packet loss statistics of the nonacknowledgement mode of the standard. The analysis is based on a non-stationary Markov chain model and its accuracy is verified by ns-2 simulations.
In this letter, we derive the asymptotic behavior of the ratio between the blocking probabilities... more In this letter, we derive the asymptotic behavior of the ratio between the blocking probabilities of burst segmentation (BS) and just-enough-time (JET) policies in an optical burst switch. It is shown that if the ratio between the offered load and the number of wavelengths, , is fixed and equals as the number of wavelengths approaches infinity, the ratio between the blocking probabilities of BS and JET approaches 1 if 1; 0.5 if = 1; and is (1) with a constant (1) 2 if 1.
This letter proposes a method to strictly prioritize switching access in Just-Enough-Time (JET)-b... more This letter proposes a method to strictly prioritize switching access in Just-Enough-Time (JET)-based optical burst switching networks. A queueing model is developed by which the blocking probability for each traffic class can be analytically evaluated. The analytical results are validated by simulations.
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